Air starter and lubricator throttle valve therefor

ABSTRACT

There is disclosed an air starter having an air motor with an inlet valve which throttles the initial pressure build-up downstream of the valve to reduce the initial shock imposed on the starter mechanism. The throttling valve has a chamber in which a trapped lubricant is positioned at the beginning of each starter operation. The trapped lubricant escapes from the chamber through an orifice to regulate the rate of opening movement of the valve and sprays the lubricant into the incoming main stream in a direction opposite to the direction of the incoming air flow to mix the lubricant uniformly with the incoming air.

[ June 11, 1974 AIR STARTER AND LUBRICATOR THROTTLE VALVE THEREFOR Inventor: Lee P. Janik, Hazardville, Conn.

Assignee: Stanadyne, 1nc., Hartford, Conn.

Filed: Nov. 9, 1972 Appl. No.: 305,004

US. Cl. 418/88, 418/100, 123/179 F, 137/5143, 184/7 D Int. C1....F02n 17/00, F16k 21/10, F010 21/04 Field of Search 418/87, 88, 100; 137/111, 137/5143; 184/7 D; 123/179 F References Cited UNlTED STATES PATENTS 3,731,763 5/1973 Thrasher et a1 184/7 D Primary Examiner-Carlton R. Croyle Assistant Examiner-John J. Vrablik Attorney, Agent, or Firm--Prutzman, Hayes, Kalb & Chilton [5 7 ABSTRACT There is disclosed an air starter having an air motor with an inlet valve which throttles the initial pressure build-up downstream of the valve to reduce the initial shock imposed on the starter mechanism. The throttling valve has a chamber in which a trapped lubricant is positioned at the beginning of each starter opera tion. The trapped lubricant escapes from the chamber through an orifice to regulate the rate of opening movement of the valve and sprays the lubricant into the incoming main stream in a direction opposite to the direction of the incoming air flow to mix the lubricant uniformly with the incoming air.

8 Claims, 1 Drawing Figure W LUBRICANT AIR STARTER AND LUBRICATOR THROTTLE VALVE THEREFOR The present invention relates to air starters and more particularly to air motors for starters of the type used for starting compression ignition engines.

When a compression ignition engine is started, its crankshaft must be rotated at a speed sufficient to compress the air in the cylinder to a pressure at which its temperature is sufficiently high to ignite the fuel injected into the cylinder. With the unavoidable leakage of some air past the piston rings, it is essential that the engine be turned over at a high rate of speed which requires a substantial power output from the starter motor. An air motor is especially adapted for such starter application since an air motor can generate a large amount of power in a small frame size and there is no reduction of its power output at low temperatures as there is with battery operated electric starters. Since a positive displacement vane-type motor in which the vanes engage an eccentric liner is normally used as a source of power for an air starter, there is a need to provide lubrication to the motor to prevent wear of the vanes. Moreover, because of the sudden rate of buildup of forces in an air starter, when energized, a severe strain is imposed on the starter mechanism when the highly pressurized air is initially delivered to the air motor at the start of the operating cycle.

It is an object of the present invention to provide an engine air starter having improved automatic control means providing a gradual, but fast, buildup of air pressure to the air starter.

Another object of this invention is to provide an improved automatic means for lubricating the starter motor. lncluded in this object is a provision of an automatic lubricating mean which results in atomized lubricant being entrained in and mixed with the incoming air supply to the starter motor.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

This invention accordingly consists in the features of construction, combination of elements and arrangements of parts which are exemplified in the construction hereinafter set forth, and the scope of the application of which will be indicated in the appended claims.

In the drawing, the single FIGURE is the side view of a starter motor, partially broken away.

Referring now to the drawing in greater detail, the starter embodying this invention is shown as comprising an air motor and a gear train 12 driven thereby. The gear train 12 terminates in a starter pinion gear 14 provided with an internal spline which mates with the high helix angle spline 16 of the driven shaft 17 so that, upon rotation of the shaft 17, the inertia of the pinion 14 causes the pinion to move to the left, as viewed on the drawing, against the bias of pinion return spring 18 to mesh with the ring gear 20 of the engine flywheel (shown in phantom).

The starter motor 10 is of the vane type having a plurality 0f vanes 22 slidably mounted in radial slots in a hub 24 mounted for rotation with shaft 26. An eccentric liner 28, disposed eccentrically with respect to the shaft 26, cooperates with the hub 24 and the vanes 22 to form a plurality of revolving chambers whose volumes vary with the rotational position of the chamber around the motor.

By virtue of the need to turn the crankshaft on the compression ignition engine at a sufficiently high speed to pressurize the charge of air in the cylinder to a level at which its temperature is sufficient to ignite the fuel which is injected near top dead center, the power output required of a starter can be in the range of 20 horsepower or more. With such a level of power output, it is apparent that the sudden inrush of air to the motor 10 would impose a severe strain on the gear train of the starter in bringing the engine rapidly up to speed from standstill. It is further apparent that the sliding contact between the vanes 22 and the liner 28 required to provide a seal against air leakage requires proper lubrication to minimize the frictional wear therebetween.

In accordance with this invention, means are provided for automatically throttling the pneumatic pressure delivered to the starter motor at the beginning of each starting operation to minimize impact shock imposed upon the flywheel and the starter mechanism and for entraining a measured charge of atomized lubricant into the air delivered to the starter at the beginning of each starting operation.

As shown in the drawing, a source of air under pressure is connected to the inlet 32 of the air motor 10 through a main air control valve 34 and a T-shaped inlet fitting 36.

The T-shaped' inlet fitting 36 has an inlet passage 38 and an outlet passage 40 disposed at a right angle thereto. The junction between the inlet passage 38 and the outlet passage 40 provides a valve seat 42 against which a shuttle valve 44 is biased by a shuttle valve return spring 46 which engages a spring seat 48 having an O-ring 50 which seals the cavity forming a spring chamber 52. A retaining ring 54 received in a groove 56 secures the spring seat 48 in its assembled position. The spring chamber 52 is provided with a lubricant inlet 58 which is connected to a source of lubricant 60 to maintain the spring chamber full of lubricant.

The spring seat 48 is provided with a central projection 62 which is coaxially aligned with a mating central recess 64 formed by the skirt of valve 44.

The head of the shuttle valve 44 is provided with a central aperture or orifice 66 and a oneway ball valve 68 which is maintained in position by an annular threaded stop member 72. When it is desired to energize the starter, the main air control valve 34 is opened by any suitable means, not shown, to introduce air under high pressure from the source 30 to the entrance passage 38 of the T-shaped fitting 36. Since the shuttle valve 44 is seated against the valve seat 42, the incoming air pressure acts on the head of the shuttle valve 44 to urge it to the left against the bias of return spring 46. As the shuttle valve 44 moves to the left, the relative movement between the shuttle valve and the central projection 62 causes the projection 62 to enter the central recess 64 of the shuttle valve to trap the lubricant therein. Because the lubricant is incompressible, the trapped lubricant resists the movement of the shuttle valve 44 to automatically limit the initial inrush of air to the air motor at a rate dependent upon the discharge of lubricant from the central cavity thereby to minimize the initial shock on the starter assembly.

As the shuttle valve 44 continues to move to theleft, the throttling action is gradually and rapidly diminished to permit the full volume of air to enter the air motor with the result that the maximum torque is delivered by Since the diameter of the central recess 64 is substantially less than the diameter of the head of the shuttle valve 44 and there is free communication between the spring chamber 52 and the source of lubrication 60, the lubricant in the central cavity 64 is pressurized to a high pressure relative to the pressure of the incoming air from source 30.

The orifice 66 permits the escape of lubricant from the central cavity 64 by unseating the ball 68 and causing the lubricant to be injected into the air stream in the inlet passage 38 of the T-shaped fitting at high speed and in a direction opposite to the direction of flow of the incoming air. As a result the lubricant is broken up into small particles and atomized and is uniformly entrained in the incoming air stream so that the air serves as an efficient carrier for distributing the lubricant within the air motor.

When the main air control valve 34 is closed at the end of a starting cycle, the pressure in the inlet 38 of the T-shaped fitting is reduced to atmospheric pressure and the shuttle piston 44 is returned toward its seat under the biasing action of valve return spring 46. Since the ball 68 returns to its seat, the return spring 46 creates a suction in the cavity 64 to draw another charge of lubricant into the cavity. In this regard, the fit between the central projection 62 and the wall of the central cavity 64 provides for a small amount of leakage to permit the lubricant to enter the cavity 64 as the shuttle valve 44 returns to a seated position under the influence of return spring 46 so that the recess 64 is filled with another charge of lubricant which may be injected into the air stream at the beginning of the next starter operating cycle.

From the foregoing, it is apparent that this invention provides for the automatic gradual and rapid buildup of power in an air starter motor to minimize the impact shock imposed on the starter mechanism at the beginning of each starter operating cycle while at the same time providing an efficient means for effectively lubricating the air motor during each operating cycle. It is further apparent that these advantages are achieved in a simple manner by minor modifications of the inlet fitting to the air motor and without the complications of any timing mechanism or feedback signals correlated with the air pressure in the air starter or the strain imposed thereon.

As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teachings of the present invention.

I claim:

1. An air starter including an air motor having an inlet suited for receiving air from a source of high pressure air to power the air motor, a valve interposed between said air source and said inlet for controlling the delivery of air to power the air motor, means for subjecting said valve to incoming air pressure to open said valve to permit the entry of pressurized air into said motor, a chamber associated with said valve, means for automatically entrapping a fluid in said chamber during the opening movement of said valve, and means for controlling the discharge of said fluid from said chamber during such opening movement to regulate the rate of opening movement of said valve to throttle the initial pressure build-up downstream of the valve to reduce the initial shock imposed on the starter.

2. The device of claim 1 wherein said fluid is an incompressible lubricant.

3. The device of claim 1 wherein an axial recess in said valve provides said fluid chamber and a mating aligned projection enters said recess during the opening movement of said valve to entrap the fluid therein.

4. The device of claim 3 wherein said projection is provided with a clearance with the walls of said fluid chamber to provide for the flow of lubricant into said chamber as the valve returns to the valve seat.

5. The device of claim 3 including a valve return spring for returning the valve to its seated position at the end of each starter operation, and means for automatically filling said fluid chamber when the valve is returned to its seat after each starter operation.

6. The device of claim 5 including a one-way valve for closing the orifice during the return of the valve toward its valve seat.

7. The device of claim 1 wherein an orifice in said valve provides for the controlled leakage of fluid from said chamber into the incoming air stream flowing through the valve.

8. The device of claim 7 wherein the orifice communicates with the air inlet upstream of the valve to discharge the entrapped fluid into the incoming air stream in a direction opposite the direction of flow of incoming air to atomize and mix the fluid with the incoming air. 

1. An air starter including an air motor having an inlet suited for receiving air from a source of high pressure air to power the air motor, a valve interposed between said air source and said inlet for controlling the delivery of air to power the air motor, means for subjecting said valve to incoming air pressure to open said valve to permit the entry of pressurized air into said motor, a chamber associated with said valve, means for automatically entrapping a fluid in said chamber during the opening movement of said valve, and means for controlling the discharge of said fluid from said chamber during such opening movement to regulate the rate of opening movement of said valve to throttle the initial pressure build-up downstream of the valve to reduce the initial shock imposed on the starter.
 2. The device of claim 1 wherein said fluid is an incompressible lubricant.
 3. The device of claim 1 wherein an axial recess in said valve provides said fluid chamber and a mating aligned projection enters said recess during the opening movement of said valve to entrap the fluid therein.
 4. The device of claim 3 wherein said projection is provided with a clearance with the walls of said fluid chamber to provide for the flow of lubricant into said chamber as the valve returns to the valve seat.
 5. The device of claim 3 including a valve return spring for returning the valve to its seated position at the end of each starter operation, and means for automatically filling said fluid chamber when the valve is returned to its seat after each starter operation.
 6. The device of claim 5 including a one-way valve for closing the orifice during the return of the valve toward its valve seat.
 7. The device of claim 1 wherein an orifice in said valve provides for the controlled leakage of fluid from said chamber into the incoming air stream flowing through the valve.
 8. The device of claim 7 wherein the orifice communicates with the air inlet upstream of the valve to discharge the entrapped fluid into the incoming air stream in a direction opposite the direction of flow of incoming air to atomize and mix the fluid with the incoming air. 